<template>
         <div>   
             <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
                    <div class="iconfont header-abs-back">&#xe685;</div>
             </router-link>
             <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
                 <router-link to="/">
                                    <div class="iconfont header-fixed-back">&#xe685;</div>
                 </router-link>
                 景点详情
             </div>
         </div>
</template>

<script>

export default {
   name: 'DetailHeader',
   data () {
       return {
       showAbs: true,
       opacityStyle: {
           opacity: 0

       }
   }
   },
   methods: {
       handleScroll () {
           
           const top = document.documentElement.scrollTop
           if (top > 60) {
               let opacity = top / 140
               opacity = opacity > 1 ? 1 : opacity
               this.opacityStyle = { opacity }
               
               this.showAbs = false
           } else {
               this.showAbs = true
           }
           
       }
   },
   activated () {
       window.addEventListener('scroll', this.handleScroll)
   },
   deactivated () {
       window.removeEventListener('scroll', this.handleScroll)
   }
}
</script>

<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position: absolute
        left: .2rem
        top: .2rem
        width: .8rem
        height: .8rem
        line-height:.8rem
        border-radius: .4rem
        text-align: center
        background: rgba(0, 0, 0, .8)
       
        .header-abs-back
            color: #fff
            font-size: .4rem
    .header-fixed
        z-index: 2
        position: fixed
        top: 0
        left: 0
        right: 0
        
        height: $headerHeight
        line-height: $headerHeight
        text-align:center
        color : #fff
        background: $bgColor
        font-size : .32rem
        .header-fixed-back
            position: absolute 
            top: 0
            left: 0
            width: .64rem
            text-align: center
            font-size: .4rem
            color: #fff
        
                    
</style>